"I'd be surprised to see the court find the entire act unconstitutional," said the former House member from Findlay, Ohio. But the lawsuit by a small accounting firm "almost certainly will come down to a 5-to-4 vote."

Oxley was a panelist at a meeting of the Pittsburgh chapter of the National Association of Corporate Directors at the Omni William Penn Hotel, Downtown. Former Pennsylvania Gov. Richard Thornburgh was moderator.

The high court is weighing the case of a Nevada-based auditor who claimed he was driven out of business by the Public Accounting Oversight Board, which Sarbanes-Oxley created. The lawsuit challenges the board's constitutionality.

"We set up the board so the Securities and Exchange Commission would appoint the commissioners, and anything they did would have to be approved by the SEC," Oxley said. Now a practicing attorney, he expects a court decision in the next few weeks.

Pending legislation in the House would exempt small companies with less than $75 million in revenue from some of the audit compliance measures imposed by Sarbanes-Oxley because they are a costly burden, said Oxley, noting the Obama administration supports an exemption.

Compliance with the law could cost $2 million a year for a company with as little as $100 million in revenue, said Harris Williams, a merger advisory firm owned by PNC Financial Services Group.

Adopted in 2002 after accounting fraud brought down Enron and WorldCom, Sarbanes-Oxley was intended to sharpen public companies' accounting and audit requirements, reduce fraud and restore investor confidence.

Thornburgh recalled sifting through the books of WorldCom when he was a court-appointed examiner working on the company's bankruptcy case. Records showed WorldCom's board had given only "cursory consideration" to many deals engineered by its CEO.

Oxley and other panelists agreed that Sarbanes-Oxley would not have prevented last year's near-collapse of the financial industry, because the law was not aimed at controlling financial institutions' investment practices or risk strategies. It also would not work to control executive pay packages or curb companies' over-leverage or abuse of derivatives, the panelists agreed. Those activities should be overseen by company boards.

The former governor said corporate compliance must be more than "just checking the boxes." Thornburgh sarcastically noted that former Enron CEO Jeffrey Skilling -- whose 2006 conviction for his role in Enron's collapse is now on appeal before the high court -- had circulated a 64-page compliance manual at the company, "and a lot of good that did."

"Nothing can beat a leader setting the tone at the top," Thornburgh said.